压电三迭片式高阶声压梯度水听器研究

该文从数学上计算了不同阶声压梯度组合对空间声场的估计误差,分析了差分通道幅度和相位不一致性对有限差分近似误差的影响,研究了水听器自噪声及模数转换量化误差对高阶水听器工作频率下限的制约关系,提出了一种由4片压电三迭片构成的高阶声压梯度水听器,尺寸为?100 mm×50 mm,能够测量声场一阶声压梯度和二阶混合声压梯度。利用有限元法计算获得平面波自由声场中水听器各通道的输出电压。计算结果表明,二阶混合声压梯度通道的输出电压响应每倍频程升高12 dB,指向性与纵向四极子声源指向性一致。     

驻波管测试下压差式光纤矢量水听器的改进

压差式矢量水听器基于声场有限差分原理进行声压梯度测量,而光纤声压传感器结构相对复杂,在工艺上难以保证传感器间的灵敏度一致性.研究了声压传感单元不一致对压差式光纤矢量水听器的影响,指出声压传感基元灵敏度不一致对实际应用中的行波场条件下的测量影响更严重,采用传统的驻波管校准后的压差式光纤矢量水听器在实际运用中就会造成声压的相位测量误差.提出了可通过一维方向上采用双干涉仪结构来克服此问题,并分析了该结构的压差式光纤矢量水听器的驻波管校准方法,依据该方法进行测试,可克服声压传感基元灵敏度不一致的影响,使其能在实际中得以应用.     

一种压电单晶矢量水听器的性能建模与分析

针对加速度型矢量水听器在低频段灵敏度偏低问题,根据铌锌酸铅-钛酸铅(PZN-PT)压电单晶的性能特点,设计了一种双悬臂梁结构压电单晶矢量水听器。建立了有限元模型,对矢量水听器的振动模态和接收性能进行了仿真计算,重点分析了几个主要材料和尺寸参数对水听器自由场灵敏度的影响。理论计算表明,采用压电单晶PZN-PT的矢量水听器经优化后其灵敏度可达-190 dB@250 Hz,与压电陶瓷PZT-5A的水听器相比,灵敏度提升了15 dB以上。     

水池中低频矢量水听器灵敏度校准

在水池中,低频声源与矢量水听器吊放在水池中央,间距小于水池的混响距离,在100～1 000 Hz范围内测量矢量水听器声压和矢量通道接收信号的灵敏度.对测量得到的灵敏度进行球面修正,可得到矢量水听器声压通道和矢量通道的灵敏度.测量结果表明,这种校准方法能校准低频矢量水听器的灵敏度,结果与理论相符.     

压电泵振动放射噪声的研究

压电泵的动力源是由压电陶瓷片及金属放大片所组成的压电振子，产生振动及噪声是这种泵所不可避免的必然现象．该文对压电泵振动放射噪声进行了研究。首先提出了由振动量计算合成声压的理论模型；然后开发了压电振子的振动及振动产生放射噪声测试的试验装置，并利用这种装置适时跟踪测试了压电泵的振动与噪声；最后把理论计算与试验测试进行了比较，其结果证明了振动量计算合成声压理论的正确性。     

基于HTCC电路的MEMS复合同振型水听器设计

矢量水听器是感知水下声信息的重要设备,基于MEMS微加工工艺研制了一种复合同振型矢量水听器,将MEMS矢量水听器芯片与压电陶瓷环在结构上组合在一起,能够同时拾取水下目标信号的标量信息和矢量信息。内部集成了HTCC调理电路,能够有效降低传感器耦合噪声,提高检测信号的信噪比。通过驻波管计量,MEMS复合式水听器的工作频率范围为20～1 000 Hz,矢量振速通道灵敏度为-170.5 d B@1 k Hz,标量声压通道灵敏度为-174.7 d B@1 k Hz。通过内嵌电路,信噪比提高了15 d B。     

用于水声通信的矢量水听器研究

水声通信系统使用传统的声压水听器接收信号,无法获得水质点的振速信息。该文研制了直径为?38 mm、高为46 mm的同振型矢量水听器,可以同步共点地获取水质点的声压信息与振速信息,解决水声通信系统对8~13 kHz的信号获取不全面问题。矢量水听器内部采用专门设计的一种共用惯性质量块的一体化三维加速度传感器,空间3个轴向的灵敏度均大于328.0 pC/g(g=9.8 m/s²)。采用PZT-5压电陶瓷圆环作为矢量水听器的声压通道,研制了具有x、y、z通道和声压p通道的矢量水听器样机,并在水池中对矢量水听器样机进行测试。测试结果表明,10 kHz处x、y、z通道的声压灵敏度级均大于-172 dB(0 dB参考值1 V/μPa),且具有良好的余弦指向性;声压通道灵敏度级达到-198 dB,可以用于水声通信中8~13 kHz信号的获取。     

MEMS压电式矢量水听器仿真与结构优化

针对微机电系统(MEMS)矢量水听器灵敏度低的问题,该文主要采用有限元频域分析法对一种新型结构的MEMS压电式矢量水听器进行了仿真与结构优化。对于一种新型具有U形槽悬臂梁结构的加速度灵敏度随压电层厚度或频率的变化进行了研究,优化了结构参数,提高了灵敏度。结果表明,当硅梁厚为16 μm,压电层厚为硅梁的51%时,可使结构的加速度灵敏度达最大。与单臂悬臂梁结构相比,双U形槽结构的加速度灵敏度及相应的矢量水听器灵敏度提高了11 dB。     

混合集成型压阻式矢量水听器设计

提出一种小型化新型压阻式矢量水听器的设计、制作工艺方法.详细分析通过混合集成工艺技术制作的压阻式矢量水听器的性能指标:灵敏度、频率响应.实际设计、制作混合集成型压阻式矢量水听器并进行测试.得出采用本工艺制作出外形尺寸只有ψp22 mm×40 mm的三维矢量水听器具有良好的三轴正交性,每轴向具有良好的"8"字型指向性,且具有良好的低频特性,声压灵敏度可达到-190 dB.     

厚度伸缩压电陶瓷振子

对厚度伸缩压电陶瓷振子的振动状态进行了分析,并得到其等效电路.推导了振子的谐振频率、反谐振频率以及等效电路参数与振子尺寸、振子材料的介电、压电、弹性常数间的关系式.最后讨论了振子的一些特性和制作.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first